Fluorides preparation

Aromatic Ring Fluorination. The formation of an aryl diazonium fluoride salt, followed by decomposition, is a classical reaction (the Schiemaim reaction) for aryl fluoride preparation (21). This method has been adapted to the production-scale manufacture of fluorobenzene [462-06-6]... 

Yields of sulfonyl fluorides prepared by ECF vary depending on the particular stmcture. Chain degradation becomes more important as the chain length kicreases (6). Yields can vary from 96% for perfluoromethanesulfonyl fluoride (7) to 43—50% for perfluorooctanesulfonyl fluoride (8). Trifluoromethanesulfonic acid can be prepared via trifluoromethanesulfenyl chloride as shown ki equations 5—7 (9). 

Ghromium(VI) Gompounds. Virtually all Cr(VI) compounds contain a Cr—O unit. The cbromium (VT) fluoride [13843-28-2], CrF, is the only binary halide known and the sole exception. This fluoride, prepared by fluorinating Cr at high temperature and pressure, easily disproportionates... 

Prepai ation ot 2-Fluoro-l -indanone, 166 Tetrabutylammonium Fluoride Preparation, 193... 

Ti, Zr, Hf, Th, U and the pentafluorides of Nb and Ta). However, many higher fluorides require the use of a more aggressive fluorinating agent or even F2 itself. Typical of the fluorides prepared by oxidative fluorination with F2 are ... 

The methanol-ether filtrate has a slight yellow color. It is not known what impurity is removed by this solvent pair. However, the submitters found that this treatment improved the yield of several aryl fluorides prepared according to the present procedure. 

The Mukaiyama condensation method was also utilized in the synthesis of several antibiotics and related bioactive substances. These syntheses include apramycin, using 4-azido-2,3,6-tri-(P-benzyl-4-deoxy-) -D-glucopyranosyl fluoride (prepared from the corresponding a-D-glucopyranosyl chloride by the AgF method ) avermectin B , using protected sugar derivatives of oleandrosyl fluoride (a-L-Ole-F) and 0-(a-L-01e)-(1 4)-a-L-0le-F (both... 

R02 represents any peroxyl radical formed from iPP, which will take part in a termination reaction with the primary peroxyl radical II). From a comparison with acid fluorides prepared from model... 

The described procedure, first applied by Colson and Freden-hagen, is useful for the preparation of a wide variety of acyl fluorides. The yields are normally 80-90%. Some examples of acyl fluorides prepared are listed in Table I. Benzoyl fluoride can also be employed as a convenient source of acetyl fluoride by reaction with acetic acid. ... 

Evidence for the existence of this type of compound appeared only in 1967. Seel, Gombler, and Budenz 145) reacted trihalomethanesulfenyl chlorides with active potassium fluoride (prepared through degradation of potassium fluorosulfinate) at 150°C in the gas phase ... 

More recently, it has been shown that topical fluoride preparations do not lead to fluoridation of the hydroxyapatite crystal [181]. Rather they form a calcium fluoride-like substance that is deposited onto the tooth surface and dissolves when the local pH is lowered [182]. The resulting dissolution adjacent to the tooth surface provides a source of soluble fluoride that can be incorporated into the mineral structure, and thus augment remineralisation. 

Chlorodifluorothioacetyl fluoride prepared by this reaction has a boiling point of 23° C. NMR characterization of this compound gave a low-field triplet and high-field doublet in a ratio of 1 2, as would be expected. However, a material boiling at 36° C had been reported earlier as chlorodifluorothioacetyl fluoride (54). This material was obtained by dehalogenation erf 2-chlorotetrafluoroethane-sulfenyl chloride with tin. In view of... 

Dimethylformamide initiation is a special case. Polythiocarbonyl fluoride prepared with this initiator, as has been stated, also has all three possible ends with —SCF=0 being present in smallest amount. Also, the polymer as isolated is free of the formamide. It is here proposed that dimethylformamide initiation may proceed as follows ... 

---